<?php

/**
 * @throws Error
 * PDO数据库
 */
class PdoDb extends DatabaseAbstract
{
    /**
     * PDO实例
     * @var PDO
     */
    protected $DB;
    /**
     * PDO准备语句
     * @var PDOStatement
     */
    protected $Stmt;
    /**
     * 最后的SQL语句
     * @var string
     */
    protected $Sql;
    /**
     * 配置信息 $config=array('dsn'=>xxx,'name'=>xxx,'password'=>xxx,'option'=>xxx)
     * @var array
     */
    protected $Config;

    /**
     * 构造函数
     * @param array $config
     */
    public function __construct($config)
    {
        $this->Config = $config;
    }

    /**
     * 连接数据库
     * @return void
     */
    public function connect()
    {
        $this->DB = new PDO($this->Config['dsn'], $this->Config['name'], $this->Config['password'], $this->Config['option']);
        //默认把结果序列化成stdClass
        $this->DB->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
        //自己写代码捕获Exception
        $this->DB->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
    }

    /**
     * 断开连接
     * @return void
     */
    public function disConnect()
    {
        $this->DB = null;
        $this->Stmt = null;
    }

    /**
     * 执行sql，返回新加入的id
     * @param string $statement
     * @return string
     */
    public function exec($statement)
    {
        if ($this->DB->exec($statement)) {
            $this->Sql = $statement;
            return $this->lastId();
        }
        $this->errorMessage();
    }

    /**
     * 查询sql
     * @param string $statement
     * @return PdoDb
     */
    public function query($statement)
    {
        $res = $this->DB->query($statement);
        if ($res) {
            $this->Stmt = $res;
            $this->Sql = $statement;
            return $this;
        }
        $this->errorMessage();
    }

    /**
     * 序列化一次数据
     * @return mixed
     */
    public function fetchOne()
    {
        return $this->Stmt->fetch();
    }

    /**
     * 序列化所有数据
     * @return array
     */
    public function fetchAll()
    {
        return $this->Stmt->fetchAll();
    }

    /**
     * 最后添加的id
     * @return string
     */
    public function lastId()
    {
        return $this->DB->lastInsertId();
    }

    /**
     * 影响的行数
     * @return int
     */
    public function affectRows()
    {
        return $this->Stmt->rowCount();
    }

    /**
     * 预备语句
     * @param string $statement
     * @return PdoDb
     */
    public function prepare($statement)
    {
        $res = $this->DB->prepare($statement);
        if ($res) {
            $this->Stmt = $res;
            $this->Sql = $statement;
            return $this;
        }
        $this->errorMessage();
    }

    /**
     * 绑定数据
     * @param array $array
     * @return PdoDb
     */
    public function bindArray($array)
    {
        foreach ($array as $k => $v) {
            if (is_array($v)) {
                //array的有效结构 array('value'=>xxx,'type'=>PDO::PARAM_XXX)
                $this->Stmt->bindValue($k + 1, $v['value'], $v['type']);
            } else {
                $this->Stmt->bindValue($k + 1, $v, PDO::PARAM_STR);
            }
        }
        return $this;
    }

    /**
     * 执行预备语句
     * @return bool
     */
    public function execute()
    {
        if ($this->Stmt->execute()) {
            return true;
        }
        $this->errorMessage();
    }

    /**
     * 开启事务
     * @return bool
     */
    public function beginTransaction()
    {
        return $this->DB->beginTransaction();
    }

    /**
     * 执行事务
     * @return bool
     */
    public function commitTransaction()
    {
        return $this->DB->commit();
    }

    /**
     * 回滚事务
     * @return bool
     */
    public function rollbackTransaction()
    {
        return $this->DB->rollBack();
    }

    /**
     * 抛出错误
     * @throws Error
     * @return void
     */
    public function errorMessage()
    {
        $msg = $this->DB->errorInfo();
        throw new Error('数据库错误：' . $msg[2]);
    }

    //---------------------

    /**
     * 单例实例
     * @var PdoDb
     */
    protected static $_instance;

    /**
     * 默认数据库
     * @static
     * @param array $config
     * @return PdoDb
     */
    public static function instance($config)
    {
        if (!self::$_instance instanceof PdoDb) {
            self::$_instance = new PdoDb($config);
            self::$_instance->connect();
        }
        return self::$_instance;
    }

    //----------------------

    /**
     * 获取PDO支持的数据库
     * @static
     * @return array
     */
    public static function getSupportDriver()
    {
        return PDO::getAvailableDrivers();
    }

    /**
     * 获取数据库的版本信息
     * @return array
     */
    public function getDriverVersion()
    {
        $name = $this->DB->getAttribute(PDO::ATTR_DRIVER_NAME);
        return array($name => $this->DB->getAttribute(PDO::ATTR_CLIENT_VERSION));
    }

}


PdoDb::instance($config);